Study On The Synthesis Of AMP Loaded Porous Silica And Its Adsorption Behavior For Cesium

The ammonium molybdophospahte (AMP) was loaded onto a poroussilica support by crystallization method in our study to synthesize a newAMP-Silica adsorbents(AMP/SiO2) and we have researched its applicationin the removal of Cs in radioactive waste water.The characterizations of the adsorbents were investigated by methodssuch as SEM, XRD, BET, TG-DTA. The results confirm the successfulloading of AMP onto the silica support. It also suggests that the AMP/SiO2shows excellent thermal stability.The adsorption of AMP/SiO2for Cs suffers little from the effect ofacid concentration. It takes just10minutes for the experiment to getequilibrium in3M nitric acid solution and the adsorption capacity canreach0.394mmol/g, the adsorption process follows a typical Langmuirmodel and the results fit quiet well for the pseudo-second kinetic ordermodel. The AMP/SiO2has high selectivity for Cs in salt solution and sufferslittle from the influence of coexistence elements metals. In0.6M NaClsolution, it takes just10minutes for the experiments to get equilibriumwith the adsorption capacity calculated to be0.39mmol/g and0.323mmol/g in batch and column operation respectively. Also, the adsorptionprocess follows a typical Langmuir model and the results fit quiet well forthe pseudo-second kinetic order model.The kinetics of the adsorption for Cs by zeolite adsorbents was quiteslow. It takes almost48hours for the zeolite to adsorb no more than65%of the Cs, and the adsorption capacity was calculate to be0.134mmol/geven after138hours. The kinetics of the adsorption for Cs by copperpotassium hexacyanoferrate silica (KCuFC/SiO2) was a little bit faster thanthat of the AMP/SiO2, however the adsorption process suffers a biginfluence from the change of the acidity and salinity of the solution. Itsadsorption capacity for Cs can calculated to be0.234mmol/g in0.6MNaCl solution, while in the presence of0.6M KCl, this value dropsdramatically to only0.042mmol/g. Thus the AMP/SiO2adsorbents pose abig advantage over the zeolites and KCuFC/SiO2.A further experiment by means of EDS and EPMA was carried out totest the distribution of Cs on the AMP silica adsorbents, and the result suggests a good adsorbability of the AMP for Cs. Thus the synthesizedadsorbents could be used as a perfect material in the removing of cesiumfrom the radio-active waste water.